Name of test

Thomas test

What it tests

Assess fixed flexion deformity of the hip

How to do it

Exaggerated lumbar lordosis may be due to spine pathology or hip pathology. Extension is the first movement the patient loses in hip pathology, resulting in fixed flexion deformity. Unilateral hip pathology can easily be detected by the Thomas test. If fixed flexion deformity is suspected, following these steps:

  • The patient should be in the supine position on the exam table. Place your hand under the patient’s spine to identify lumbar lordosis.
  • Have the patient flex the knee and hip on the unaffected side by pulling the knee to the chest and holding it there. This will cause the lumbar lordosis to straighten out. The other leg remains flat (extended) on the exam table.
  • If the patient has a fixed flexion deformity, the thigh on the affected side will lift off the table. Measure the angle between the affected thigh and the table to determine the degree of the fixed flexion deformity.

If the patient has bilateral hip flexion deformity, the Thomas test cannot be used. See Alternative to Thomas test in bilateral FFD

Video: Thomas test

Video: Thomas test and modified Thomas test

The normal response

The extended thigh remains flat on the table when the opposite thigh is pulled to the chest

What it means if not normal

Flexion contracture of the iliopsoas muscle (fixed flexion deformity of the hip)


  • Do not overflex the hip, which would cause the pelvis to rotate posteriorly and would result in a false positive.
  • Note that it is difficult to elicit the Thomas test in obese patients.


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